Microinvasive lung adenocarcinoma review brain CT is not used as a routine screening modality. Microinvasive lung adenocarcinoma belongs to the relatively early stage, and because lymph node metastasis and distant organ metastasis rarely occur, brain metastasis rarely occurs. Routine review does not include brain CT examination because the probability of metastasis is low, and the examination will increase radiation and is not necessary. For microinvasive lung adenocarcinoma with lower differentiation and higher malignancy, brain CT examination once a year can be considered to evaluate whether there is metastasis. Of course, if the patients themselves have symptoms of headache and dizziness, they can consider brain CT or magnetic resonance examination at this time to assess the presence of metastasis.